import java.util.Stack;

class MyQueue {
    public Stack<Integer> s1;
    public Stack<Integer> s2;


    public MyQueue() {
         s1=new Stack<>();
         s2=new Stack<>();
    }
    
    public void push(int x) {
       s1.push(x);




    }
    
    public int pop() {
        if(empty()){
            return -1;
        }
        if(s2.isEmpty()){
            while(!s1.isEmpty()){
                s2.push(s1.pop());
            }
        }
        return s2.pop();

    }
    
    public int peek() {
        if(empty()){
            return -1;
        }
        if(s2.isEmpty()){
            while(!s1.isEmpty()){
                s2.push(s1.pop());
            }
        }
        return s2.peek();

    }
    
    public boolean empty() {
     return  s1.isEmpty()&&s2.isEmpty();

    }
}
